1. Field of the Invention
The invention generally relates to an illumination device and a method of controlling the same. More specifically, the invention relates to an illumination device and a method for controlling the illumination device that uses a light detecting element for detecting brightness in an environment.
2. Description of Related Art
Light emitting diode (LED) light sources have advantages of energy saving, being environmental, a long life span, and a quick response time, and are currently used popularly in city road lights.
In the Taiwan Patent-issued No. 1316592, an LED lamp that could be remote controlled and includes a light source, a first and second light detecting element, and a control box is disclosed. The control box includes a memory and a communication chip. The first detecting element is used to detect the brightness in an environment. The second detecting element is used to detect the operating condition of the light source. Detected information is stored and recorded in the memory of the control box. The communication chip transmits the detected information to a remote control station.
In the patent application of the Taiwan publication No. 200721063, a display device that could automatically adjust brightness according to the brightness of the environment and includes a display control circuit, a brightness control unit, and a display light source is disclosed. The display device further includes a brightness adjustment circuit electrically connected to the display control circuit and the brightness control unit. The brightness adjustment circuit includes a light detection unit, a buffer unit and a coupling unit. The light detection unit is used to detect the brightness of the environment, and dynamically outputs a corresponding voltage signal.
In the U.S. Pat. No. 7,518,320, an exemplary LED control circuit, including an observation circuit, a sampling circuit, a controller, and a regulating circuit is disclosed. The observation circuit is used to detect brightness of ambient light so as to generate a voltage signal according to the detected brightness. The sampling circuit generates a control signal according to the voltage signal. The controller generates a selection signal according to the control signal. The regulating circuit connects to an LED driving circuit and is used to adjust the operation status.
In the U.S. Pat. No. 6,441,557, a circuit for controlling a light source that adjusts its brightness based on the ambient brightness is disclosed. A light sensor produces a signal corresponding to the ambient brightness. The signal is used for modulating the pulse width to control a transistor to change an average current of a light source, so the brightness of the light source will change according to the ambient brightness.